Objective lens device, optical pickup device, and optical information recording and/or reproduction device

ABSTRACT

This invention relates to an objective lens driving device which moves an objective lens; an optical pickup device, comprising this objective lens driving device, which condenses a light beam onto the information recording surface of an optical disc; and an optical information recording and/or reproduction device, comprising this optical pickup device, which drives in rotation an optical disc and moves the optical pickup device to record and/or reproduce information signals onto or from the information recording surface. Two printed coil boards, with a first printed coil with a first shape formed on at least one face and a second printed coil with a second shape formed on the other face, are provided in parallel in an objective lens driving device of this invention, and a moveable portion on which an objective lens is provided is connected with the two printed coil boards; also, a magnet is positioned between the two printed coil boards provided in parallel. A driving current is supplied to each of the first and second printed coils to drive the objective lens in the vertical and/or lateral directions. By means of the objective lens driving device of this invention, twice the propelling force is generated by the two printed coil boards positioned on either side of the magnet, so that driving control of the objective lens can be performed satisfactorily using a simple construction.

The present application is a 371 application of PCT/JP02/06082 filed onJun. 18, 2002.

TECHNICAL FIELD

This invention relates to an objective lens driving device capable ofmoving an objective lens in a desired direction; an optical pickupdevice comprising this objective lens driving device, and capable ofcondensing a light beam on the information recording portion of anoptical disc and of receiving the return light beam; and an opticalinformation recording and/or reproduction device, comprising thisoptical pickup device, which rotates an optical disc and moves theoptical pickup device to irradiate the information recording portionwith a light beam to perform recording and/or reproduction ofinformation.

BACKGROUND ART

In the prior art, in general, an optical information recording andreproduction device comprises a disc rotation mechanism to driverotation of an optical disc at a prescribed speed; an objective lensdriving device, having an objective lens which condenses a light beam onthe information recording portion of the optical disc; a slide base onwhich the objective lens driving device is mounted; and a pickupmovement device which moves the slide base along the informationrecording portion of the optical disc.

As conventional objective lens driving devices used in such opticalinformation recording and reproduction devices, for example, devicessuch as that described in Japanese Patent Laid-open No. 63-177323 areknown. This conventional objective lens driving device has a magneticcircuit portion having a magnet and yoke, and an electromagnetic coil;the electromagnetic coil is positioned within the magnetic fluxgenerated by the magnetic circuit portion. By passing a current throughthis electromagnetic coil, an electromagnetic force is generated due tothe magnetic force of the magnet. By fixing either the electromagneticcoil or the magnetic circuit portion to the objective lens assembly, theobjective lens can be driven.

FIG. 22 is used as FIG. 1 in the above-mentioned Japanese PatentLaid-open No. 63-177323, and is a drawing showing the yoke and frameused in the objective lens driving device. In FIG. 22, symbol 1 denotesa frame formed from magnetic material. The frame 1 comprises a plate inwhich is provided an aperture 2 in the substantial center; at twolocations corresponding to peripheral edges of this aperture 2 areprovided, by raising upward the inner-edge portions, inside yokes 3 a, 3b. Outer yokes 4 a, 4 b are provided, by raising upward the outer-edgeportions of the frame at two locations, so as to oppose the inside yokes3 a, 3 b.

Magnets 5 a, 5 b are provided integrally, bonded using adhesive to thefaces of these outer yokes 4 a, 4 b facing the inner yokes 3 a, 3 b. Agap of prescribed size is provided between each of the magnets 5 a, 5 band the inside yokes 3 a, 3 b. In these gaps are inserted a portion of apair of coil members installed on a moveable member supporting theobjective lens, not shown, such that the magnets 5 a, 5 b do not makecontact with the respective inside yokes 3 a, 3 b.

The pair of coil members comprises a pair of focusing coils mounted soas to surround the inside yokes 3 a, 3 b, and a tracking coil fixed onthe sides of the magnets 5 a, 5 b of the focusing coils. The pair ofcoil members are mounted on the moveable member, and the moveable memberis movably supported by the frame 1 via a support mechanism. A pair ofsupport pins 6 a, 6 b are provided in the frame 1 to support the supportmechanism.

However, in a conventional objective lens driving device such as this, apair of inside and outside yokes 3 a, 3 b and 4 a, 4 b are provided inopposition on the frame 1 of magnetic material, and magnets 5 a, 5 b arefixed and supported by the outside yokes 4 a, 4 b, while at the sametime, coil members are mounted so as to surround the inside yokes 3 a, 3b in opposition to the magnets 5 a, 5 b, so that the following problemarises.

That is, because a pair of inside and outside yokes 3 a, 3 b and 4 a, 4b is required on the frame 1, the construction of the frame 1 is complexand machining properties are poor. Moreover, because the positioning ofthe inside yokes 3 a, 3 b and outside yokes 4 a, 4 b must be performedwith high precision, assembly is difficult, and results in increasedcosts.

DISCLOSURE OF THE INVENTION

In light of these points, in the present invention, an objective lensdriving device, optical pickup device, and optical information recordingand/or reproduction device are proposed, which enable reduction of thenumber of parts through a simplified construction and improvement ofproductivity of parts used, as well as facilitating assembly, therebycontributing to reduction of overall device costs.

In order to solve the above-described problems and attain the aboveobject, an objective lens driving device of this application has aconfiguration in which two printed coil boards are provided in parallel,with a first printed coil with a first shape formed on at least the faceof one side and a second printed coil with a second shape formed on theface of the other side, with a moveable portion on which the objectivelens is provided, connected with the two printed coil boards, and with amagnet positioned between the two printed coil boards provided inparallel; and is characterized in that a driving current is supplied toeach of the first and second printed coils to drive the objective lensin the vertical and/or lateral directions.

Also, a pickup device of this application has a configuration in whichtwo printed coil boards provided in parallel, with a first printed coilhaving a first shape are formed on at least the face of one side and asecond printed coil with a second shape formed on the face of the otherside, with a moveable portion on which the objective lens is provided,connected with the two printed coil boards, and with a magnet positionedbetween the two printed coil boards provided in parallel; and ischaracterized in that at least tracking and focusing error signals aredetected from a light beam transmitted through the objective lens,driving currents are supplied to the first and second printed coilsbased on the error signals, and controlled driving of the objective lensin the tracking direction and/or focusing direction is performed.

Further, an optical information recording and/or reproduction device ofthis application comprises a disc rotation device which drives therotation of an optical disc; an objective lens driving device which usesan objective lens, provided on a moveable portion driven by a coilmember thereon through the action of the magnetic force of a magnet onthe coil member, to condense a light beam on the information recordingportion of an optical disc; a slide base on which is mounted theobjective lens driving device and which is formed from non-magneticmaterial; and a pickup movement device which moves the slide base in theradial direction along the information recording portion of the opticaldisc; and is characterized in that a magnet is directly fixed onto theslide base. By means of the above-described configuration, in anobjective lens driving device of this application, double the propulsiveforce occurs through the two printed coil boards placed on both sides ofthe magnet, so that driving control of the objective lens can beperformed satisfactorily using a simple construction.

In an optical pickup device of this application, the construction of theoverall device can be simplified and the number of parts reduced,assembly can be facilitated, and the precision of the positioning ofparts can be increased.

Further, in an optical information recording and/or reproduction deviceof this application, the stable fixation of various electronic parts andelectrical equipment can be secured, mounting procedures can besimplified and devices reduced in size, and the number of parts can bedecreased.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing in exploded form a first embodimentof an optical pickup device of this invention;

FIG. 2 is a perspective view used to explain the process of manufactureof the slide base of the first embodiment of an optical pickup device ofthis invention;

FIG. 3 is a perspective view showing the slide base and objective lensdriving device of the first embodiment of an optical pickup device ofthis invention;

FIG. 4 is a perspective view showing in enlarged form the principalportion of the slide base shown in FIG. 3;

FIG. 5 is a perspective view of the slide base shown in FIG. 3, seenfrom the bottom side;

FIG. 6 is an explanatory drawing showing the cross-section along theoptical system of the first embodiment of an optical pickup device ofthis invention;

FIG. 7 is a cross-sectional view showing in enlarged form the principalportion of the optical pickup device shown in FIG. 6;

FIG. 8 is a perspective view of the first embodiment of an opticalpickup device of this invention, seen from the bottom side;

FIG. 9 shows the first embodiment of the printed coil of a printed coilboard of the first embodiment of an optical pickup device of thisinvention; FIG. 9A is an explanatory drawing of a printed coil forfocusing, seen from the top side, and FIG. 9B is an explanatory drawingof a printed coil for tracking, seen from the top side through thebottom side;

FIG. 10 is an explanatory drawing of the connection state of the printedcoils for focusing of a pair of printed coil boards of the firstembodiment of an optical pickup device of this invention, seen from thetop side;

FIG. 11 is an explanatory drawing of the connection state of the printedcoils for tracking of a pair of printed coil boards of the firstembodiment of an optical pickup device of this invention, seen from thetop side through the bottom side;

FIG. 12 compares and explains the force directions (F), magnetic flux(B) and electric current directions (I) based on new and old coilmembers; FIG. 12A is an explanatory drawing for the case of a pair ofprinted coil boards of an embodiment of an optical pickup device of thisinvention, and FIG. 12B is an explanatory drawing for the case of aconventional wound coil;

FIG. 13 shows a second embodiment of the printed coil of a printed coilboard in the first embodiment of an optical pickup device of thisinvention; FIG. 13A is an explanatory drawing of a printed coil andmagnet for focusing seen from the top side, FIG. 13B is an explanatorydrawing of a printed coil and magnet for focusing seen from the top sidethrough the bottom side, FIG. 13C is an explanatory drawing of a printedcoil for focusing seen from the top side, and FIG. 13D is an explanatorydrawing of a printed coil for tracking seen from the top side throughthe bottom side;

FIG. 14 is a perspective view showing an optical information recordingand/or reproduction device of this invention;

FIG. 15 is a perspective view showing the feed-screw driving device ofthe optical pickup device of an optical information recording and/orproduction device of this invention;

FIG. 16 is an explanatory block diagram showing in summary theconfiguration of an embodiment of an optical information recordingand/or reproduction device of this invention;

FIG. 17 is a perspective view of a second embodiment of an opticalpickup device of this invention, seen from the top side;

FIG. 18 is a plane view of the second embodiment of an optical pickupdevice of this invention;

FIG. 19 is an explanatory drawing showing a cross-section along theoptical system of the second embodiment of an optical pickup device ofthis invention;

FIG. 20 is an explanatory drawing showing the optical system of thesecond embodiment of an optical pickup device of this invention;

FIG. 21 is a perspective view showing the principal components of theslide base of the second embodiment of an optical pickup device of thisinvention; and,

FIG. 22 is a perspective view showing the frame and yoke used in theobjective lens driving device of a conventional optical pickup device.

BEST MODE FOR CARRYING OUT THE INVENTION

Below, aspects of this invention are explained, referring to theattached drawings. As shown in FIGS. 1 through 8, the optical pickupdevice 20 shown as a first embodiment in a preferred aspect of thisinvention comprises a slide base 21, in turn comprising a base member 22and cover member 23; a two-axis actuator 24, illustrating one specificexample of an objective lens driving device, and mounted on base member22; a laser light source 25 which emits a light beam for recordingand/or reproduction of information signals; and a photodetector 26 whichreceives a returning light beam reflected from the information recordingportion (information recording surface) of the optical disc afteremission from the laser light source 25.

As shown in FIGS. 1 and 2, the base member 22 of the slide base 21 has amounting portion 22 a the plane shape of which is substantiallyrectangular, and which protrudes in an oblique direction at one cornerportion. This base member 22 is formed integrally from a circuit core 27a forming a portion of an electrical circuit formed in the shape ofcircuit wiring by a conductive metal plate (for example, a copperplate), and from an outer foundation 27 b formed from insulatingmaterial, which exposes the necessary portion of the circuit core 27 aand covers the other portions.

As the material of the outer foundation 27 b, for example, a nonmagneticresin material (for example, a liquid crystal polymer) is used. However,the material of the outer foundation 27 b is not limited to resinmaterial, and a metal material which is not magnetic may be used, aswell as a ceramic material or similar.

This base member 22 is manufactured by taking the circuit core 27 a as askeleton and adding on the outer foundation 27 b. For example, afterusing the circuit core 27 a as an insert which is set in a die, thematerial of the outer foundation 27 b is packed into the vacant space inthe die. Thus, a base member 22 in which the outer foundation 27 b isbonded with the circuit core 27 a can be formed integrally by injectionmolding.

At this time, the circuit core 27 a is linked to an outer frame 28 by aplurality of support pieces 28 a. As shown in FIG. 2, the outer frame 28forms a rectangular framework, and plays the role of supporting thecircuit core 27 a via the plurality of support pieces 28 a duringmolding. The circuit core 27 a is connected to an auxiliary frame 29 viaa plurality of terminal pieces 29 a which become terminals forconnection to external wires. This outer frame 28, auxiliary frame 29and plurality of support pieces 28 a are unnecessary for the molded basemember 22, and so are cut away and removed during post-processing afterinjection molding of the outer foundation 27 b.

As shown in FIG. 1 and FIG. 3, at the tip of the mounting portion 22 aof the base member 22 is provided a pedestal 30, formed by raising thematerial upward. In the pedestal 30 is provided a first concave portion31 a in which is housed the laser light source 25; and in the mountingportion 22 a is provided a second concave portion 31 b, in which ishoused the photodetector 26. The second concave portion 31 b is formedas a square depression of prescribed size in the substantial center ofthe mounting portion 22 a. One edge of the second concave portion 31 breaches to the pedestal 30, and the first concave portion 31 a is formedin the top face of the pedestal 30 so as to be open on the side of thesecond concave portion 31 b.

By exposing the circuit core 27 a in an appropriate shape, electricalcircuit portions 32, 33 are provided in the first and second concaveportions 31 a, 31 b. That is, an electrical circuit 32 for the lightsource, having a base portion on which is mounted the laser light source25 and a plurality of terminal portions arranged on the periphery of thebase portion, is provided in the first concave portion 31 a. And, anelectrical circuit 33 for detection, having a base portion on which ismounted the photodetector 26 and a plurality of terminal portionsarranged on the periphery of the base portion, is provided in the secondconcave portion 31 b.

The laser light source 25 emits a light beam for recording and/orreproduction of information signals; for example, a semiconductor laser(laser diode) may be employed. The laser light source 25 is mounted onthe light source electrical circuit 32 with the light beam emissionaperture facing in the horizontal direction, as shown in FIG. 6. Thephotodetector 26 receives the returning light beam reflected by theinformation recording surface to read information signals, focusingerror signals and tracking error signals; for example, a photodiode ICmay be employed. This photodetector 26 is mounted on the detectorelectrical circuit 33, with the light beam receiving aperture facingupward.

As shown in FIG. 4, the light source electrical circuit 32 and the laserlight source 25 mounted thereon are electrically connected by aplurality of wire bonding leads 34 a. And, the detector electricalcircuit 33 and the photodetector 26 mounted thereon are electricallyconnected by a plurality of wire bonding leads 34 b. A step of anappropriate height is provided between the surface of the light sourceelectrical circuit 32 and the surface of the detector electrical circuit33, with consideration paid such that the light beam emitted from thelaser light source 25 positioned above does not interfere with thephotodetector 26 installed below.

Above the photodetector 26, a prism 35 is positioned which transmits thelight beam emitted by the laser light source 25, as well as guiding thereturning light beam to the photodetector 26. The prism 35 is housedwithin a guide groove 36a provided in the mounting portion 22 a. Theprism 35 is positioned such that a portion overlaps in the verticaldirection with substantially the entirety of the photodetector 26, witha prescribed gap between.

The prism 35 comprises a block-shape member having an inclinedreflecting face 35 a on one side in the length direction of therectangular solid; a first diffraction grating 35 b is provided in aface on one end side in the length direction, and a second diffractiongrating 35 c is provided in the end face on the other side in the lengthdirection. The first diffraction grating 35 b of the prism 35 faces thelaser light source 25, and the prism 35 is set with the length directionparallel to the direction of propagation of the light beam. The prism 35is fixed on the base member 22 by a prism holder 37 mounted in themounting portion 22 a.

As shown in FIGS. 1 and 3, the prism holder 37 comprises a member with atunnel structure having a mating concave portion 37 a which mates withthe prism 35; flange portions 37 b protruding in a directionintersecting the mating concave portion 37 a are provided at both endsof the tunnel portion. Latching clasps 37 c, protruding downward andhaving flexibility, are provided at the tips of each of the flangeportions 37 b. By latching the pair of latching clasps 37 c with a pairof clasp holes 36 b in the mounting portion 22 a, the prism holder 37 ismounted in the base member 22. In this way, the light beam emitted fromthe laser light source 25 is incident on the first diffraction grating35 b of the prism 35, advances within the prism, and is emitted from thediffraction grating 35 c on the opposite side. The returning light beamreflected by the information recording surface is incident again on thesecond diffraction grating 35 c, and here is refracted by a prescribedangle and propagates toward the opposite face 35 a. This light beam isreflected by the opposite face 35 a and propagates downward, is emittedfrom the bottom face of the prism 35, and is incident on thelight-receiving face of the photodetector 26.

Further, by providing a cutout portion 22 b in the base member 22, aplurality of terminals 28 b are exposed, and by providing an aperturehole 22 c, numerous terminals 29 a are exposed. And, by providing acutout in the outer foundation 27 b corresponding to the numerousterminals 29 a, a connector portion 45 for connection to external wiringis provided. This connector portion 45 is configured as a ZIF-lock typeconnector, but this invention is not thus limited; for example, anon-ZIF-type connector can be used, in which external wires are insertedand are fixed in place by the pressure of the connector itself.

The base member 22 with such an electrical circuit incorporated as thecircuit core 27 a can be connected with the outer foundation 27 b usingthe above-described circuit core 27 a as an insert, to enable simplemass production by injection molding. Hence a base member 22 withintegrally formed connector portion 45 can be fabricated easily by asingle injection molding process.

As shown in FIGS. 1 and 3, a two-axis actuator 24 is mounted integrally,as a specific example of an objective lens driving device, on the upperface of the base member 22. This two-axis actuator 24 comprises asupport member 39 fixed to an adjustment plate 38, four support wires 40fixed to one edge of the support member 39, and a two-axis moveableportion 41 elastically supported by the four support wires 40.

The support member 39 is formed from insulating material, and is fixedto the adjustment plate 38 by fastening screws or other fastening means.The height of the adjustment plate 38 can be adjusted in the verticaldirection relative to the base member 22. By adjusting the amount ofprotrusion upward of the base member 22 using this adjustment plate 38,the height of the two-axis actuator 24 can be adjusted. This adjustmentplate 38 is fixed to the base member 22 by adhesive, by welding, or byother fastening means.

The four support wires 40 fixed to each edge of the support member 39are formed from conductive material having appropriate elasticity. Thefour support wires 40 are arranged in parallel so as to be symmetricalvertically and laterally, and the tips are fixed to the two-axismoveable portion 41. The two-axis moveable portion 41 comprises a lensholder 42 formed from insulating material, two printed coil boards 43 a,43 b fastened to and supporting the lens holder 42 and forming a pair,and an objective lens 44 also fastened to the lens holder 42.

As shown in FIGS. 3 and 6, the lens holder 42 of the two-axis moveableportion 41 has a holder portion 42 a to which the objective lens 44 isfixed, a balance portion 42 b for weight balance of the holder portion42 a, and right and left linking wall portions 42 c, 42 c linked betweenthe holder portion 42 a and balance portion 42 b with a prescribed gapbetween.

The holder portion 42 a of the lens holder 42 has an overhanging portionwhich overhangs a side similarly to eaves; the objective lens 44 isfitted into the upper portion of a through-hole provided in thisoverhanging portion, and is fixed into place with adhesive or otherfastening means in an integral construction. The first printed coilboard 43 a is mounted on the inside of the balance portion 42 b of thelens holder 42, and the second printed coil board 43 b is mounted on theinside of the holder portion 42 a.

As shown in FIGS. 9 to 11, the two printed coil boards 43 a, 43 b havesubstantially the same shape and construction, with symmetricaldirections of winding of the printed coils, and are configured with twotypes of printed coils superimposed and affixed. In FIG. 9, on what iscalled the top side, the printed coil shown is formed on the near sideof the board, and on what is called the bottom side, the printed coil isformed on the far side of the board.

On the top side (the side near the magnet 46, described below) of thepair of printed coil boards 43 a, 43 b, as shown in FIG. 9A,horizontally long printed coils 200 a, 200 b and 201 a, 201 b forfocusing are provided, divided into upper and lower and formed so as towind about each. On the bottom sides of each printed coil board 43 a, 43b (the side far from the magnet 46) are provided printed coils fortracking 202 a, 202 b and 203 a, 203 b, made somewhat vertically long,divided into left and right and formed so as to wind about each.

FIG. 10 shows an embodiment of the printed coils for focusing 200 a, 200b and 201 a, 201 b provided on the pair of printed coil boards 43 a, 43b positioned on either side of the magnet 46. In FIG. 10, an upper-sideprinted coil 200 a formed so as to wind, for example, clockwise from theoutside toward the inside, and a lower-side printed coil 201 a formed soas to wind counterclockwise from the inside to the outside, are providedon the top side of the printed coil board (first printed coil board) 43a placed on the far side of the magnet 46.

Also, an upper-side printed coil 200 b formed so as to wind, forexample, clockwise from the outside toward the inside, and a lower-sideprinted coil 201 b formed so as to wind counterclockwise from the insideto the outside, are provided on the top side of the printed coil board(second printed coil board) 43 b placed on the near side of the magnet46. Because FIG. 10 is a perspective view, the actual printed coils 200b, 202 b of the second printed coil board 43 b are formed such that,when seen from the front, the clockwise and counterclockwise directionsare winding directions opposite those shown.

As shown in FIG. 10, on the right and left edges of the top sides of thepair of printed coil boards 43 a, 43 b, three connection portions eachare provided, for a total of six connection portions 204 a, 205 a, 206a, 207 a, 208 a, 209 a. The connection portion 204 a on the upper-leftof the first printed coil board 43 a is connected to the outer-peripheryend of the upper-side printed coil 200 a. From here, the upper-sideprinted coil 200 a winds clockwise toward the inside, and theinner-periphery end is connected to the first through-hole 211 a on theupper side.

The first through-hole 211 a penetrates the first printed coil board 43a and is connected on the bottom side to a lower-side secondthrough-hole 211 b. The second through-hole 211 b is connected to theinner-periphery end of the lower-side printed coil 201 a. From here thelower-side printed coil 201 a winds counterclockwise toward the outside,and the outer-periphery end is connected to the connection portion 208 aat the center-right.

The connection portion 208 a at the center-right of the second printedcoil board 43 b is connected to the outer-periphery end of theupper-side printed coil 200 b. From here, the upper-side printed coil200 b winds clockwise toward the inside, and the inner-periphery end isconnected to a third through-hole 211 c on the upper side.

The third through-hole 211 c penetrates the second printed coil board 43b and is connected on the back side to the lower-side fourththrough-hole 211 d. The fourth through-hole 211 d is connected to theinner-periphery end of the lower-side printed coil 201 b. From here, thelower-side printed coil 201 b winds counterclockwise toward the outside,and the outer-periphery end is connected to the connection portion 206 aat the lower-left.

As shown in FIG. 11, on the right and left edges of the bottom sides ofthe pair of printed coil boards 43 a, 43 b, three connection portionseach are provided, for a total of six connection portions 204 b, 205 b,206 b, 207 b, 208 b, 209 b. The connection portion 207 b on theupper-right of the first printed coil board 43 a is connected to theouter-periphery end of the right-side printed coil 202 a. From here, theright-side printed coil 202 a winds counterclockwise toward the inside,and the inner-periphery end is connected to the fifth through-hole 212 aon the right side.

The fifth through-hole 212 a penetrates the first printed coil board 43a and is connected on the bottom side with the left-side sixththrough-hole 212 b. The sixth through-hole 212 b is connected to theinner-periphery end of the left-side printed coil 203 a. From here, theleft-side printed coil 203 a winds clockwise toward the outside, and theouter-periphery end is connected to the connection portion 205 b at thecenter-left.

The connection portion 205 b at the center-left of the second printedcoil board 43 b is connected to the outer-periphery end of the left-sideprinted coil 203 b. From here, the left-side printed coil 203 b windsclockwise toward the inside, and the inner-periphery end is connected tothe left-side seventh through-hole 212 c.

The seventh through-hole 212 c penetrates the second printed coil board43 b and is connected on the bottom side to the right-side eighththrough-hole 212 d. The eighth through-hole 212 d is connected to theinner-periphery end of the right-side printed coil 202 b. From here, theright-side printed coil 202 b winds counterclockwise toward the outside,and the outer-periphery end is connected to the connection portion 209 bat the lower-right.

The two printed coil boards 43 a, 43 b having the above configurationare positioned in parallel, with a prescribed gap between, as shown inFIGS. 6 and 7, and are fixed in place to the lens holder 42. Each of theends of the four support wires 40 a, 40 b, 40 c, 40 d and the connectionwires 214 a, 214 b comprising two conductive wires are connected to theconnection portions 204 a to 209 a and 204 b to 209 b of the two printedcoil boards 43 a, 43 b.

In other words, as shown in FIG. 10, the first support wire 40 a passesthrough the connection portion 204 a at the upper-left of the secondprinted coil board 43 b and is connected to the connection portion 204 aat the upper left of the first printed coil board 43 a. The secondsupport wire 40 b is connected to the connection portion 206 a at thelower-left of the second printed coil board 43 b. And, one end of thefirst connection wire 214 a is connected to the center-right connectionportion 208 a of the first printed coil board 43 a, while the other endis connected to the center-right connection portion 208 a of the secondprinted coil board 43 b.

As shown in FIG. 11, the third support wire 40 c passes through theupper-right connection portion 207 b of the second printed coil board 43b and is connected to the upper-right connection portion 207 b of thefirst printed coil board 43 a. The fourth support wire 40 d is connectedto the lower-right connection portion 209 b of the second printed coilboard 43 b. And, one end of the second connection wire 214 b isconnected to the center-left connection portion 205 b of the firstprinted coil board 43 a, while the other end is connected to thecenter-left connection portion 205 b of the second printed coil board 43b.

Each of the other ends of the four support wires 40 a to 40 d isprovided with an end extending somewhat past the block-shape supportmember 39. The support wires 40 a to 40 d and connection wires 214 a,214 b are connected to the connection portions 204 a to 209 a and 204 bto 209 b of the printed coil boards 43 a, 43 b by soldering or otherjoining means.

Each of the other ends of these support wires 40 a to 40 d is connectedto a wiring pattern of a flexible printed circuit board. The wiringpattern of the flexible printed circuit board is connected to a wiringpattern provided directly on the slide base 21. A portion of the wiringpattern is wired in a prescribed shape on the base member 22, and aportion is assembled in one place and collected at the connector portion45.

In this embodiment, a configuration is employed in which the two printedcoil boards 43 a, 43 b are affixed to the lens holder 42 with adhesive;but this invention is not thereby limited, and for example, duringinjection molding of the lens holder 42, a two-color molding or othermethod may be used in integral molding.

As shown in FIGS. 6 and 7, between the two printed coil boards 43 a, 43b, a magnet 46 is provided so as to intervene, with a prescribed gap,between the printed coils. The magnet 46 comprises a rectangular solid,with one magnetized pole; for example, the north pole or south pole maybe made to face the surface of the first printed coil board 43 a, with adifferent pole on the opposite side opposing the surface of the secondprinted coil board 43 b. Of course depending on the coils used, a magnetwith two magnetized poles may be used, positioned with the same poleopposing the printed coil boards 43 a, 43 b.

A support base 47, protruding upward, is provided on the base member 22for the purpose of supporting and fixing in place the magnet 46 in aprescribed position and at a prescribed height. The magnet 46 is mounteddirectly onto and fixed in place by this support base 47, without anyintervening parts. The surfaces of each of the printed coils of thefirst and second printed coil boards 43 a, 43 b are configured to beparallel or substantially parallel to the opposing faces of the opposingmagnet 46.

Further, a pair of clamping pieces 47 a, 47 a which clamp the magnet 46is provided on the support base 47. By fitting the magnet 46 betweenthese clamping pieces 47 a, 47 a and placing the magnet on the supportbase 47, the magnet 46 can be positioned in the above-described paralleldirection. The clamping force of the pair of clamping pieces 47 a alonemay be employed; but it is preferable that adhesive be used to fix themagnet 46 to the support stand 47.

In this way, by directly fixing the magnet 46 onto the base member 22,use of a part corresponding to a conventional yoke is abolished, and thenumber of parts can be reduced. And, by employing as the material of thebase member 22 a nonmagnetic resin material, further cost reductions canbe achieved. Because the magnet 46 can be mounted on the support base 47merely by latching using the pair of clamping pieces 47 a, the assemblyprocess can be made extremely easy, and positioning can be performedwith higher precision.

The two printed coil boards 43 a, 43 b are positioned in parallel atpositions substantially symmetric with respect to the magnet 46, suchthat the combined propulsion point due to the printed coils 200 a, 201a, 202 a and 203 a (or 200 b, 201 b, 202 b and 203 b) is substantiallythe same as the center of the magnet 46. Below the objective lens 44,the optical axis of which is set in the vertical direction, a reflectingmirror 48 is positioned which reflects the incident light beam to changeits direction of propagation. The reflecting mirror 48 is fixed on aninclined face of the mirror cradle 49 provided on the base member 22.Due to the inclined face of the mirror cradle 49, the reflecting face ofthe reflecting mirror 48 is set in an inclined plane which makes anangle which is substantially 45° with the horizontal plane. The centerof the reflecting face of the reflecting mirror 48 coincides orsubstantially coincides with the center of the optical axis of the lightbeam emitted from the laser light source 25.

Thus when the light beam, after passing through the prism 35 andpropagating horizontally, reaches the reflecting mirror 48, the beam isbent 90° or in a right angle by the reflecting face and propagatesupward, passing through the objective lens 44. After being condensed bythe objective lens 44, the light beam is incident on the informationrecording surface of the optical disc 50. After being reflected by theinformation recording surface, the light beam again passes through theobjective lens 44 and propagates downward. When this returning lightbeam reaches the reflecting mirror 48, it is bent 90° by the reflectingface, and then propagates in a horizontal direction orthogonal to theoptical axis of the objective lens 44.

By this two-axis actuator 24, a force propelling the lens holder 42fixed to the pair of printed coil boards 43 a, 43 b can be generated atwill in the vertical or lateral directions according to the currentsflowing in the four support wires 40 a to 40 d. As a result, due to theoccurrence of this propelling force, the two-axis moveable portion 41,having the pair of printed coil boards 43 a, 43 b, the objective lens 44and the lens holder 42, is moved in two mutually orthogonal directions,and focusing and/or tracking control driving of the light beam passingthrough the objective lens 44 is executed.

A cover member 23, the object of which is to be guided by the guide axiswhile keeping dust from the two-axis actuator 24, is mounted onto thebase member 22 on which is positioned the two-axis actuator 24 with theabove-described configuration. This cover member 23, while mounted ontothe base member 22, is fixed in place by fastening screws or otherfastening means, to constitute the slide base 21.

As shown in FIG. 1 and FIG. 5, the cover member 23 has an upper faceportion 23 a covering the upper face of the base member 22 and a sideface portion 23 b surrounding the periphery of this upper face portion23 a, and is formed as a lid-shaped member with hole openings in thelower face. Hence the upper face portion 23 a of the cover member 23 hasa shape substantially similar to, but somewhat enlarged compared to, theplane shape of the base member 22; a principal bearing 52 is provided onone side in the length direction, and a secondary bearing 53 is providedon the other side in the length direction.

The principal bearing 52 of the cover member 23 has two bearingportions, opposed across a prescribed gap, in the width direction of theupper face portion 23 a, and bearing holes 52 a with common shaft centerline are provided in each bearing portion. A first guide shaft,described below, is slideably inserted into these bearing holes 52 a. Abearing groove 53 a, open in the side direction, is provided in thesecondary bearing 53, and a second guide shaft, described below, isslideably latched in this bearing groove 53 a. On the bottom face of thebearing groove 53 a is provided a guide protruding portion 54 to reducelooseness with the second guide shaft and to alleviate frictionresistance during sliding.

At the substantial center of the upper face portion 23 a of the covermember 23 are provided an aperture window 55 to expose the objectivelens 44 of the two-axis actuator 24, and two aperture grooves 56 a, 56 bto allow vertical motion of the pair of printed coil boards 43 a, 43 b.In the inner face of the upper face portion 23 a above the two-axisactuator 24, are provided a first escape concave portion 57 a to avoidinterference with the two-axis moveable portion 41, a second escapeconcave portion 57 b to avoid interference with the support member 39,and a third escape concave portion 57 c to avoid interference with theprism holder 37, as shown in FIG. 6.

As described above, the base member 22 and cover member 23 areattachably and removeably fixed by fastening screws 70 as one specificexample of fastening means, as shown in FIG. 8. Consequently in the basemember 22, as shown in FIG. 3, insertion holes 68 penetrating in thevertical direction are provided in three places in the outer foundation27 b. Corresponding to these, screw holes 69 are provided in threeplaces in the cover member 23 to coincide with the insertion holes 68 ofthe base member 22, as shown in FIG. 5.

After mounting the cover member 23 by fitting onto the base member 22,by passing screw shafts through each of the insertion holes 68 andscrewing the tips into the screw holes 69, and then tightening thefastening screws 70, the slide base 21 is combined into a whole by thethree fastening screws 70, as shown in FIG. 8.

A plurality of ribs 71 are provided in the bottom surface of the basemember 22 of this slide base 21, and by these ribs 71 the base member 22is strengthened. On the bottom surface of the base member 22, aplurality of metal exposure portions 72 a, 72 b and circuit exposureportions 73 a, 73 b, 73 c are formed by exposing a portion of thecircuit core 27 a. The object of the metal exposure portions 72 a, 72 bis not to constitute an electrical circuit, but to support or fix parts.On the other hand, the circuit exposure portions 73 a to 73 c areconfigured as a portion of an electrical circuit.

Penetrating holes 74 are provided in each of a pair of first metalexposure portions 72 a, 72 a; a pair of leg pieces of the adjustmentplate 38 are inserted into these penetrating holes 74. The pair of legpieces is bonded by solder-welding to the first metal exposure portion72 a, and by this, the adjustment plate 38 is fixed to the base member22. Clasp holes 22 d are provided in each of the pair of second metalexposure portions 72 b, and the pair of latching clasps 37 c of theprism holder 37 are inserted into these clasp holes 22 d. The pair oflatching clasps 37 c is jointed by solder-welding to the second metalexposure portions 72 b, and by this, the prism holder 37 is installed onthe base member 22. A plurality of capacitors 75 a are mounted bysolder-welding onto the first circuit exposure portion 73 a, whichconstitutes a portion of an electrical circuit. Similarly, variableresistances 75 b are mounted by solder-welding onto the second circuitexposure portion 73 b which constitutes a portion of an electricalcircuit. It is preferable that the surfaces of these first and secondcircuit exposure portions 73 a, 73 b be subjected to solder plating,gold plating, or other plating treatment (the metal exposure portions 72a, 72 b may also be subjected to plating treatment). By performing suchplating treatment, conductors can be joined even at comparatively lowtemperatures, so that even chip parts which are relatively vulnerable tohigh temperatures, such as capacitors and resistors, can easily bemounted by soldering onto the electrical circuit.

The third circuit exposure portion 73 c prevents electrostatic breakdownof the semiconductor laser used as the laser light source 25. Bygrounding (GND) one of the metal exposure portions of the third circuitexposure portion 73 c and setting the other metal exposure portion toland level (LD), a land for ground function which prevents electrostaticbreakdown of the semiconductor laser is effected.

By the base member 22 comprising the circuit core 27 a and outerfoundation 27 b, capacitors, resistors and other electronic parts can bedirectly mounted on the base member 22 without requiring the use offlexible flat cables (FF cables), so that the optical pickup device 20can be made compact and lightweight. And, optical parts and theobjective lens driving device, the purpose of which is not electricalconnections, can be fixed in place mechanically to the base member 22using solder-welding, so that fixing of optical parts and similar to thebase member 22 can be performed simply and reliably.

Operation to record and/or reproduce information signals by an opticalpickup device 20 with such a configuration may be performed, forexample, as follows. As shown in FIG. 6, a light beam emitted from thelaser light source 25 propagates in a horizontal direction and isincident on the first diffraction grating 35 b of the prism 35, isdivided into three rays by the first diffraction grating 35 b, andpropagates in a horizontal direction. After passing through the prism35, the beam is emitted from the side of the second diffraction grating35 c, and is incident on the reflecting mirror 48. When incident on thereflecting mirror 48, the light beam is reflected upward by thereflecting surface and the propagation path is changed by 90°; the beamis then incident on and condensed by the objective lens 44 above.

Having been condensed by the objective lens 44, the light beam isincident on the information recording surface of the optical disc 50positioned above, and is reflected by the surface and returns. That is,the light beam reflected by the information recording surface returnsalong the optical path previously traveled, propagating downward andpassing through the objective lens 44. After passing through theobjective lens 44, the direction of the light beam is changed 90° by thereflecting mirror 48 and the beam propagates in a horizontal direction,and is incident on the prism 35 from the second diffraction grating 35c. The returning light beam, when incident on the prism 35, is somewhatrefracted upwards by the second diffraction grating 35 c, and isreflected by the reflecting face 35 a. Upon being reflected by thereflecting face 35 a, the direction of propagation of the light beam ischanged to the downward direction, and after emission from the bottomface of the prism 35 the beam is incident on the light-receiving portionof the photodetector 26.

By reading the state of the light beam thus emitted from the laser lightsource 25 and incident on the photodetector 26, information signalsrecorded in advance on the information recording surface can be read(reproduced), and in addition focusing error signals and tracking errorsignals occurring at the time of readout can simultaneously be read.Further, by emitting a light beam with high output from the laser lightsource 25, the light beam can be used to write (record) new informationsignals on the information recording surface.

An optical pickup device 20 having a configuration such as describedabove can be used in a disc recording/reproduction device 80, a specificexample of which is for example an optical information recording and/orreproduction device with the configuration shown in FIG. 14. This discrecording/reproduction device 80 comprises a disc rotation device 81,which chucks and drives in rotation an optical disc at a prescribedspeed (for example, at constant linear velocity); the above-describedoptical pickup device 20, which performs recording (writing) andreproduction (readout) of information signals on the informationrecording surface of the optical disc mounted on and driven in rotationby the disc rotation device 81; a pickup movement device 82 which causesthe optical pickup device 20 to advance and retreat so as to approachand move away from the disc rotation device 81; and a chassis 83 onwhich the above are mounted.

As the optical disc, for example, a read-only optical disc on which havebeen recorded in advance music signals as audio information, image andmusic signals as video information, or other information signals; awrite-once (append-type) optical disc onto which music, image, or otherinformation signals can be recorded once; or an optical disc which canbe repeatedly recorded any number of times (rewritable), or variousother optical discs can be used. The optical disc is not limited tothese optical disc types; for example, a magneto-optical disc, in whicha magnetic thin film layer is formed on the surface of a thin disc andan optical head and magnetic head are used to write information to orread information from the magnetic thin film layer, as well as othertypes of disc-shape recording media, can be used.

The chassis 83 of the disc recording/reproduction device 80 has asubstantially rectangular or other planar shape, and a reinforcingperipheral wall 83 a is provided by continuously raising the peripheryupward. At four places on the peripheral wall 83 a are provided supportprotrusions 83 b for use in mounting the chassis 83 in, for example, aCD (compact disc) player or DVD (digital versatile disc) player or otherelectronic equipment.

A first aperture portion 84 a is provided at substantially the center ofthis chassis 83, and a second aperture portion 84 b is provided on anend. The disc rotation device 81 is placed between the first apertureportion 84 a and the second aperture portion 84 b of the chassis 83, andthe optical pickup device 20 is positioned so as to straddle the firstaperture portion 84 a. The pickup movement device 82 is positioned onone side of the optical pickup device 20.

The disc rotation device 81 comprises a motor baseplate 85, a spindlemotor 86 fixed to the motor baseplate 85, and a turntable 87 providedintegrally with the rotation portion of the spindle motor 86. Thespindle motor 86 is mounted on the motor baseplate 85, which is of thinsheet metal; the motor baseplate 85 is fixed in place on the chassisusing fastening screws or other fastening means. One end of an FF cable88 is fixed in place using adhesive or other fastening means to theupper surface of the motor baseplate 85.

The spindle motor 86 has a stationary portion which is fixed to themotor baseplate 85 and a rotation portion which is rotatably supportedby the stationary portion; a turntable 87 is provided integrally on therotation shaft which is the center of rotation of the rotation portion.The turntable 87 has a mating portion which mates with the center holeof the optical disc, and a placement portion, continuous with the lowerportion of the mating portion, and on which is placed the periphery ofthe center hole of the optical disc. Within the mating portion isincorporated a magnet which attracts a chuck ring, not shown. The chuckring is attracted by this magnet, and by clamping the periphery of thecenter hole of the optical disc between the chuck ring and the placementportion, the optical disc is chucked and is in a state enabling rotationtogether with the turntable 87. The pickup movement device 82 comprisesa pair of guide shafts 90 a, 90 b which guide the motion of the opticalpickup device 20, and a feed-screw driving device 91 which causes theoptical pickup device 20 to advance and retreat. The pair of guideshafts 90 a, 90 b are positioned in parallel in positions so as tosurround both sides of the spindle motor 86. Each of the guide shafts 90a, 90 b is formed from a rod-shaped member the outer surface of which issmooth.

The first guide shaft 90 a slideably penetrates the bearing hole 52 a ofthe principal bearing 52 provided on the cover member 23, constituting aportion of the slide base 21 of the optical pickup device 20, and bothends are supported by the adjustment plate 92. The second guide shaft 90b slideably penetrates the bearing groove 53 a of the secondary bearing53 provided in the cover member 23, and both ends are supported by thechassis 83. The adjustment plate 92 is mounted on the chassis 83 in amanner enabling change of the attitude, and by changing the attitude ofthe adjustment plate 92, the degree of parallelism of the pair of guideshafts 90 a, 90 b can be adjusted.

Among the pair of guide shafts 90 a, 90 b, the first guide shaft 90 a issupported by a pair of shaft support pieces 93 a, 93 a provided on theadjustment plate 92. Each of the shaft support pieces 93 a is providedsuch that the shaft restraint pieces 93 b form a pair. By using afastening screw 93 c to screw the shaft restraint pieces 93 b in place,each of the ends of the first guide shaft 90 a is fixed to the shaftsupport pieces 93 a. The second guide shaft 90 b is supported by a pairof shaft support pieces 94 a, 94 a provided on the chassis 83. A shaftrestraint piece 94 b is provided on each shaft support piece 94 a so asto form a pair. By using a fastening screw 94 c to screw the shaftrestraint pieces 94 b in place, both of the ends of the second guideshaft 90 b are supported by the chassis 83.

The feed-screw driving device 91 is installed on the adjustment plate92. As shown in an enlarged view in FIG. 15, the feed-screw drivingdevice 91 comprises a feed screw 95, feed motor 96, support plate 97,and power transmission member 98. The feed screw 95 is formed byproviding on the outer face of a round rod, shorter than the guideshafts 90 a, 90 b, a single screw groove 95 a extending helically oversubstantially the entire length in the axis direction. This feed screw95 also serves as a rotation shaft for the feed motor 96 which is thedriving source, and is directly driven in rotation.

Next, the configuration of a circuit for driving and controlling theabove-described disc recording/reproduction device 80 is explained. FIG.16 shows a specific example of the circuit configuration of a discrecording/reproduction device 80 of this embodiment, and is anexplanatory block diagram of a device capable of both recording(writing) and reproduction (reading) of information signals.

In FIG. 16, the symbol 110 denotes a system control device which drivesand controls the spindle motor 86 and feed motor 96. This system controldevice 110 is connected so as to be capable of exchanging signals with aservo circuit 111 which executes servo control of the optical pickupdevice 20. The system control device 110 is connected to an operationpanel 112, on which are provided a power supply switch and variousoperation buttons and similar. The optical pickup device 20 is connectedto a light beam driving and detection circuit 113; the output of thisdriving and detection circuit 113 is supplied to the system controldevice 110 and to the servo circuit 111. Further, the driving anddetection circuit 113 is connected to a recording/reproduction circuit116, which is connected to an input terminal 114 and an output terminal115.

By a disc recording/reproduction device 80 configured in this way,recording and/or reproduction of information signals onto and from anoptical disc 50 is performed in, for example, the following manner.First, by operating the operation panel 112, a user inputs operationinformation to the system control device 110, and based on thisoperation information, control signals are output from the systemcontrol device 110 to the spindle motor 86, feed motor 96, and servocircuit 111.

When control signals are supplied to the spindle motor 86 from thesystem control device 110, the spindle motor 86 is driven in rotationsuch that, for example, the linear velocity is constant. Also, the feedmotor 96 is driven by control signals from the system control device110, and through driving of the feed motor 96, the optical pickup device20 is moved such that the light beam irradiates a desired position onthe information recording surface of the optical disc 50.

Then, information signals from the input terminal 114 are, for example,supplied via the recording/reproduction circuit 116 to the light beamdriving and detection circuit 113. By controlling the light beam outputin the optical pickup device 20 according to signals from this drivingand detection circuit 113, information signals from the input terminal114 are recorded on the information recording surface of the opticaldisc 50. Also, information signals recorded in advance on theinformation recording surface of the optical disc 50 are detected by thedriving and detection circuit 113, and the detected information signalsare output from the output terminal 115 via the recording/reproductioncircuit 116.

Together with this, in the driving and detection circuit 113 thetracking error signal and focusing error signal of the light beam aredetected, and these error signals are supplied to the servo circuit 111.By this, control signals are supplied to the optical pickup device 20from the servo circuit 111, and control and driving of tracking and/orfocusing by the above-described two-axis actuator 24 are performed.Also, by supplying operation signals from the operation panel 112 to thesystem control device 110, the optical pickup device 20 can be moved todesired recording or reproduction positions, or otherwise controlled.And, the light beam from the optical pickup device 20 comprising thetwo-axis actuator 24 is incident on the information recording surface ofthe optical disc 50, by which means information signal recording andreproduction are performed.

In the two-axis actuator 24 of this embodiment, by using the two printedcoil boards 43 a, 43 b as described above, control and driving notpossible using conventional wound coils can be performed. This point isexplained referring to FIGS. 12A and 12B.

In the case of the conventional wound coil 120 shown in FIG. 12B, if forexample the direction of magnetic flux B is toward the left, then thedirection of the current I is reversed on the side of one face of themagnet 121 and on the side of the opposing face, so that the wound coil120 generates a propulsion force F which is opposite for eachhalf-perimeter. These opposing propulsion forces F cannot be made tocancel each other out, and so the wound coil 120 cannot be adopted infocusing and tracking control and driving.

On the other hand, in the two-axis actuator 24 of this embodiment, asshown in FIG. 12A, by changing the winding direction of the printed coilthe direction of flow of the current on the side of one face of themagnet and on the side of the opposing face can be set to be the samedirection. As a result, the propulsion force can be arranged to be inthe same direction on the far side of the magnet 46 and on the nearside, and consequently by using two printed coil boards 43 a, 43 b,focusing and tracking control and driving become possible, as describedabove.

FIG. 13 shows another aspect of two printed coil boards. In FIG. 13,FIG. 13B shows a focusing printed coil 221 a formed on the magnet sideof a first printed coil board 220 a, positioned on the far side of themagnet 46. FIG. 13A shows four tracking printed coils 223 a, 224 a, 225a, 226 a, formed on the surface opposite the magnet side. These fourtracking printed coils 223 a to 226 a are formed as four divisions,right and left, and upper and lower.

FIG. 13C shows a focusing printed coil 221 b formed on the magnet sideof a second printed coil board 220 b, positioned on the near side of themagnet 46. And, FIG. 13D shows four tracking printed coils 223 b, 224 b,225 b, 226 b, formed on the surface opposite the magnet. These fourtracking printed coils 223 b to 226 b are formed as four divisions,right and left, and upper and lower. Two magnets 46 a, 46 b arepositioned with their N and S poles set as shown in the figure relativeto these printed coils.

These first and second printed coil boards 220 a, 220 b are similarlysupported by the above-described four support wires 40 a to 40 d, and adriving current is supplied via these four support wires 40 a to 40 d.For example, the first support wire 40 a is connected to the connectionportion 204 a at the upper left of the pair of printed coil boards 220a, 220 b. The second support wire 40 b is connected to the connectionportion 206 b at the lower left of the pair of printed coil boards 220a, 220 b. The third support wire 40 c is connected to the connectionportion 207 a at the upper right of the pair of printed coil boards 220a, 220 b. And, the fourth support wire 40 d is connected to theconnection portion 209 b at the lower right of the pair of printed coilboards 220 a, 220 b.

The upper-left connection portion 204 a connected to the first supportwire 40 a is connected to the outer-periphery ends of the upper-leftprinted coils 223 a, 223 b of the tracking printed coils shown in FIGS.13A and 13D. From here the printed coils 223 a, 223 b wind clockwisetoward the inside to form windings. The inner-periphery ends of theprinted coils 223 a, 223 b penetrate the printed coil boards 220 a, 220b and are connected to the inner-periphery ends of the lower-leftprinted coils 224 a, 224 b on the bottom side.

These printed coils 224 a, 224 b are formed so as to windcounterclockwise toward the outside. The outer-periphery ends of theprinted coils 224 a, 224 b are connected to the outer-periphery ends ofthe lower-right printed coils 226 a, 226 b. These printed coils 226 a,226 b are formed so as to wind clockwise toward the inside. Theinner-periphery ends of these printed coils 226 a, 226 b pass throughthe printed coil boards 220 a, 220 b and are connected to theinner-periphery ends of the upper-right printed coils 225 a, 225 b onthe bottom side.

These printed coils 225 a, 225 b are formed so as to windcounterclockwise toward the outside. The outer-periphery ends of theseprinted coils 225 a, 225 b are connected to the upper-right connectionportion 207 a connected to the third support wire 40 c. By this, aseries circuit of printed coils 223 a to 226 a and a series circuit ofprinted coils 223 b to 226 b, formed respectively on the printed coilboards 220 a, 220 b, are provided in parallel.

And, by for example passing a current from the first support wire 40 atoward the third support wire 40 c, the current flows clockwise throughthe printed coils 223 a, 226 a and 223 b, 226 b, and flowscounterclockwise through the printed coils 224 a, 225 a and 224 b, 225b.

On the other hand, as shown in FIGS. 13A and 13D, when two magnets 46 a,46 b are magnetized with N poles upward and S poles downward, arightward propulsive force is formed on each of the printed coil boards220 a, 220 b.

As shown in FIGS. 13B and 13C, the lower-left connection portion 206 bconnected to the second support wire 40 b is connected to theouter-periphery ends of the outside printed coils 221 a, 221 b forfocusing. From here, the printed coils 221 a, 221 b are formed so as towind clockwise toward the inside.

The inner-periphery ends of the printed coils 221 a, 221 b pass throughthe printed coil boards 220 a, 220 b and are drawn to the outsides ofthe printed coils 221 a, 221 b on the bottom side, and are connected tothe lower-right connection portion 209 b connected to the fourth supportwire 40 d.

By this, the printed coils 221 a, 221 b formed on each of the printedcoil boards 220 a, 220 b are provided in parallel. And, by for examplepassing a current from the second support wire 40 b toward the fourthsupport wire 40 d, the current flows clockwise through the printed coils221 a, 222 a.

On the other hand, as shown in FIGS. 13B and 13C, when two magnets 46 a,46 b are magnetized with N poles upward and S poles downward, an upwardpropulsive force is formed on the printed coil boards 220 a, 220 b.

Thus in a device employing two printed coil boards 220 a, 220 b havingthe above configuration, similarly to the embodiment described above,propulsive forces in the vertical and lateral directions act on the pairof printed coil boards 220 a, 220 b according to the current passedbetween the supporting wires 40 a, 40 b or the supporting wires 40 c, 40d. And through the occurrence of these propulsive forces, the two-axismoveable portion 41 on which are provided the printed coil boards 220 a,220 b and objective lens 44 is moved. AS a result, tracking and/orfocusing control and driving can be performed for the light beam passingthrough the objective lens 44.

In such a configuration in which printed coils are connected inparallel, even when for example the printed coil boards are fabricatedwith multiple layers to raise the sensitivity, layers can easily beinterconnected. And, in such a configuration with printed coilsconnected in parallel, the connection portions 205 a, 205 b and 208 a,208 b provided in the left and right centers of the above-describedprinted coil boards 43 a, 43 b, 220 a, 220 b are not used, and so theseconnection portions need not be provided.

The above-described objective lens driving device (two-axis actuator 24)has a configuration in which a moveable portion has provided two printedcoil boards 43 a, 43 b or 220 a, 220 b in parallel with a first printedcoil with a first shape formed on at least one side and a second printedcoil with a second shape formed on the other side, and with an objectivelens 44 provided on the two printed coil boards, and a magnet ispositioned between the two printed coil boards provided in parallel; bysupplying a driving current to the first and second printed coils todrive the objective lens in the vertical and/or lateral directions,twice the propulsive force is applied to the two printed coil boardspositioned on either side of the magnet. Consequently, although theconstruction is simple, control and driving of the objective lens can beperformed satisfactorily.

FIGS. 17 through 21 show a second embodiment of an optical pickup deviceof this invention. The optical pickup device 120 of the secondembodiment combines the base member 22 and cover member 23 of theabove-described first embodiment to constitute a slide base 121 as asingle member combining the functions of both. The optical pickup device120 is configured from this slide base 121 and the two-axis actuator 122and optical equipment 123 mounted thereon.

As shown in FIGS. 17 to 19, the slide base 121 has a substantiallyrectangular base portion 121 a, and a side face portion 121 formed bycontinuously lifting upward two sides in the length direction and oneside in the width direction of the base portion 121 a. This slide base121 comprises an outer foundation formed from an insulating resinmaterial (for example, a liquid crystal polymer), and a circuit core ofa conductor, formed from an insert using the outer foundation, withnecessary portions exposed to the outside and other portions buriedwithin the outer foundation.

However, the material of the outer foundation is not limited toinsulating resin materials, and metal can be used if electricallyinsulating; in addition, ceramics or similar may be employed.

On one side in the length direction X of the slide base 121 are provideda pair of first bearing portions 124, 124 in the width direction Yintersecting [the length direction X], across a prescribed gap. In eachof these first bearing portions 124 is provided a bearing hole 124 awith the same center, penetrating in the width direction Y. A secondbearing portion 125 protruding on the side opposite the first bearingportions 124 is provided on one side in the width direction Y, on theopposite side in the length direction X, of the slide base 121. Abearing groove 125 a, open on the outside in the length direction X, isprovided in this second bearing portion 125.

At the substantial center of the slide base 121, a two-axis actuator 122having substantially the same configuration as the above-describedtwo-axis actuator 24 is configured integrally. The two-axis actuator 122comprises a support member 127 fixed to the slide base 121, four supportwires 128 fixed to the support member 127, and a two-axis moveableportion 129 fastened to the end portions of the four support wires 128.The support member 127 comprises a substantially rectangular blockformed from an insulating material, in which are provided a plurality ofscrew insertion holes 127 in the length direction, with prescribed gapstherebetween. And, a tunnel portion 130 enabling passage of the lightbeam is provided in the lower portion of the center of the supportmember 127, in the length direction.

The four support wires 128 are formed of a conductive material with anappropriate elasticity, and are supported at the four corners of thesupport member 127 so as to be mutually parallel. The two-axis moveableportion 129 supported by the ends of these four support wires 128comprises a lens holder 131 formed from an insulating material, and twoprinted coil boards 132 a, 132 b, fixed and supported by the lens holder131 and forming a pair. The lens holder 131 has a holder portion 131 a,balance portion 131 b, and connecting wall portion 131 c. A penetratinghole is provided in the holder portion 131 a, and the objective lens 133is mounted integrally so as to block this penetrating hole, usingadhesive or other fastening means.

The two printed coil boards 132 a, 132 b are positioned so as to beparallel with a prescribed gap between, and are fixed to the lens holder131. The ends of the four support wires 128 and the two connection wiresare connected to connection portions on the two printed coil boards 132a, 132 b. Also, each of the ends of the four support wires 128 isconnected to a wiring pattern on the flexible printed circuit board 134.

Similarly to the above-described first embodiment, a magnet 135 isprovided to intervene, separated by a prescribed gap from each of theprinted coils, between the two printed coil boards 132 a, 132 b. And, inorder to support and fix the magnet 135 in a prescribed position and ata prescribed height, a support base 136, protruding upward, is providedon the slide base 121. The magnet 135 is placed directly onto and fixedon this support base 136, and set such that each of the printed coilfaces of the two printed coil boards 132 a, 132 b are parallel orsubstantially parallel to the respective opposing faces of the magnet135.

On the support base 136 are provided a pair of clamping pieces 137, 137.By fitting the magnet 135 between these clamping pieces 137, 137 andplacing the magnet on the support base 136, the magnet 135 can bepositioned and fixed to the slide base 121. The magnet 135 is set suchthat the center substantially coincides with the combined propulsionpoint arising due to the printed coils of the two printed coil boards132 a, 132 b.

A reflecting mirror 138 which modifies the direction of propagation ofthe light beam is positioned below the objective lens 133, the opticalaxis of which is set in the vertical direction. The reflecting mirror138 is fixed on an inclined face of a mirror cradle 139 provided on theslide base 121, with the reflecting face set so as to make substantiallya 45° angle with the horizontal plane. The center of the reflecting faceof the reflecting mirror 138 is set so as to be the same orsubstantially the same as the center of the optical axis of the lightbeam emitted from the laser light source 140, positioned so as to opposethe reflecting mirror.

The laser light source 140 is mounted on and electrically connected tothe electrical circuit 141 formed by the circuit core, at the end of theslide base 121 in the length direction X on the side of the secondbearing portion 125. On the inside of the laser light source 140 on theelectrical circuit 141, a photodetector 142 is mounted and electricallyconnected. As shown in FIG. 19, the laser light source 140 is set at aposition a step higher than the photodetector 142; hence the light beamemitted from the laser light source 140 does not strike thephotodetector 142, but propagates upward. The prism 143 and theabove-described reflecting mirror 138 are positioned along the opticalaxis of the light beam emitted from the laser light source 140.

The wiring pattern of the above-described flexible printed circuit board134 is electrically connected to the circuit core forming the electricalcircuit 141. And as shown in FIG. 21, except for the portion on whichthe laser light source 140 and photodetector 142 are mounted and thenecessary peripheral portions, the circuit core is covered by the outerfoundation, and the laser light source 140 and photodetector 142 areexposed in the circuit exposure portion 144 of the electrical circuit.

FIG. 17 and FIG. 18 show the state in which the electrical circuit 141of the circuit core is exposed, equivalent to an intermediate productprior to becoming the molded slide base 121. On the side face of theslide base 121, numerous terminals 145 constituting a portion of thecircuit core and a connector portion 146, formed from a portion of theouter foundation, are provided integrally. The connector portion 146 isprovided for connection with outside wiring, and has a non-ZIF typeconnector construction; however, a ZIF-type connector may also be used.

FIG. 21 shows the state in which, except for the necessary portion(circuit exposure portion 144) of the electrical circuit 141 in FIG. 17,the upper face of the circuit core is covered by the outer foundation.The laser light source 140 and photodetector 142 mounted on the circuitexposure portion 144 are electrically connected to the surroundingelectrical circuit by wire bonding 147 or by other connection means. Theprism 143 is positioned above the photodetector 142, and the light beamemitted from the laser light source 140 is incident on the prism 143from the diffraction grating 35b. The returning light beam input to theprism 143 from the second diffraction grating 35 c is reflected by thereflecting face 35 a and is incident on the light-receiving portion ofthe photodetector 142.

The laser light source 140, photodetector 142 and prism 143 are similarto those described above in the first embodiment, and so the samesymbols are assigned to the same portions, and explanations are omitted.Also, the symbol 143 a shown in FIG. 17 is a flange portion with a hole,used to fix the prism 143 to the slide base 121. A protrusion isprovided in the slide base 121 corresponding to this flange portion 143a; after fitting the protrusion into the hole, by solder-welding the tipof the protrusion, the prism 143 is positioned and fixed to the slidebase 121.

By means of this optical pickup device 120 of the second embodimentalso, advantageous results similar to those of the optical pickup device20 of the above-described first embodiment are obtained. That is, theslide base 121 is formed from an insulator, and by insert molding in theinterior or on the surface, an electrical circuit is formed, while alsoendowing the configuration with the functions of connectors havingelectrodes; consequently connection to a connection implement havingelectrodes of external wiring, and direct connection to the electricalcircuit within the slide base 121, are possible. As a result, use ofconnectors employed in connections with FF cables and external wiring isreduced insofar as possible, the number of parts used is decreased, andassembly processes are facilitated.

In addition, the semiconductor laser 140 and photodetector 142 can bedirectly mounted on the slide base 121, and are connected to theelectrical circuit 141 within the slide base 121 by wire bonding 147;hence the use of expensive laser couplers, hologram laser units andsimilar can be abolished or reduced, and high-precision assembly ofoptical system equipment is made possible.

The present invention is not limited to the embodiments explained above;and although, in the above embodiments, examples of application to adisc recording/reproduction device capable of both recording andreproduction of information was explained, it is of course possible toapply this invention to a disc recording device or to a discreproduction device capable only of either recording or reproduction.Further, a two-axis actuator was employed as an objective lens drivingdevice, and an example was explained in which a wire support method wasused as a specific example; however, this invention is not therebylimited, and, for example, a leaf-spring method in which the moveableportion is supported by a leaf spring, or a hinge method in which themoveable portion is supported by a hinge mechanism, can be adopted.

In this way, the present invention can be modified variously within therange in which there is no deviation from the essence of the invention.

INDUSTRIAL APPLICABILITY

By an objective lens driving device of this application, twice thepropelling force is generated through two printed coil boards positionedon either side of a magnet, so that a simple configuration can beemployed for satisfactory driving and control of the objective lens.

Also, by an optical pickup device of this application, the overalldevice construction can be simplified and the number of parts reduced,while also enabling improved ease of assembly and enhanced assemblyproperties, as well as higher precision of positioning of individualcomponents, thereby reducing the cost of the device as a whole.

And, by an optical information recording and/or reproduction device ofthis application, the various electronic components and electricalequipment can be fixed in place reliably, mounting means can besimplified, the device made more compact, and the number of componentsreduced.

1. An optical pickup device, comprising: an objective lens drivingdevice which, by causing the magnetic force of a magnet to act on a coilmember, drives a moveable portion on which is provided said coil member,causing to move an objective lens provided on said moveable portion; anda slide base, on which is fixed a stationary portion which supports saidmoveable portion of said objective lens driving device, and at least oneportion of which is formed from non-magnetic material, wherein whereinsaid moveable portion has two printed coil boards on which are formedprinted coils, said magnet is positioned between said two printed coilboards, and said magnet is directly fixed onto said slide base, whereinsaid slide base has a circuit core, comprises a conductor forming anelectrical circuit which supplies electric current to said objectivelens driving device, and an outer foundation, comprising an insulator,on which said objective lens driving device is installed, and wherein bycovering said circuit core with said outer foundation while exposing aportion of said circuit core, a circuit exposure portion which affordsexposure for electrical connections is provided on said electricalcircuit.
 2. The optical pickup device according to claim 1 wherein saidprinted coil board is formed by superimposing two types of printed coilswith different winding methods, such that propelling forces aregenerated in two orthogonal directions due to the magnetic force of saidmagnet.
 3. The optical pickup device according to claim 1, wherein saidcircuit core has one or more terminals connected to outside wiring, saidouter foundation forms a connector portion using said terminals, andoutside wiring is electrically connected to said circuit core via saidconnector portion.
 4. The optical pickup device according to claim 1,wherein at least one among the laser light source which emits said lightbeam toward the information recording surface of the optical disc andthe photodetector which receives the returning light beam afterreflection by said information recording surface is mounted on andelectrically connected to said circuit exposure portion of said circuitcore, without being covered by a package.
 5. The optical pickup deviceaccording to claim 4, wherein either said laser light source or saidphotodetector, or both said laser light source and said photodetector,are mounted on said circuit exposure portion and are connected to saidcircuit core by wire bonding.
 6. The optical pickup device according toclaim 1, wherein a land portion which can be solder-bonded is providedon said circuit exposure portion, and capacitors, resistors, and otherelectronic components are mounted on said land portion.
 7. The opticalpickup device according to claim 6, wherein the surface of said landportion is subjected to solder, gold, or other plating treatment,enabling mounting on the land portion of said capacitors, resistors, andother electronic components.
 8. The optical pickup device according toclaim 1, wherein a metal exposure portion exposing a portion of thecircuit core is provided on said circuit core for the purpose of solderbonding, and an adjustment plate supporting said objective lens drivingdevice is fixed to said metal exposure portion by solder bonding.
 9. Theoptical pickup device according to claim 1, wherein a metal exposureportion exposing a portion of the circuit core is provided on saidcircuit core for the purpose of solder bonding, and a prism holdercovering a prism through which said light beam passes or other holdersupporting optical components is fixed by solder bonding to said metalexposure portion.
 10. The optical pickup device according to claim 1,wherein said outer foundation comprises a liquid crystal polymer orother resin material.
 11. An optical information recording andreproduction device, comprising: a disc rotation device, which drives inrotation an optical disc; an objective lens driving device, which drivesa moveable portion on which a coil member is provided by causing themagnetic force of a magnet to act on the coil member, and causes anobjective lens provided on said moveable portion to condense a lightbeam onto the information recording portion of said optical disc; aslide base, on which is mounted said objective lens driving device, andwhich is formed from a non-magnetic material; and a pickup movementdevice, which moves said slide base in the radial direction along saidinformation recording portion of said optical disc, wherein saidmoveable portion has two printed coil boards on which are formed printedcoils, said magnet is positioned between said two printed coil boards,and said magnet is directly fixed onto said slide base, wherein saidslide base has a circuit core comprising a conductor which forms anelectrical circuit supplying an electrical current to said objectivelens driving device, and an outer foundation comprising an insulator onwhich is installed said objective lens driving device, and wherein bycovering the circuit core with said outer foundation, while exposing aportion of said circuit core, a circuit exposure portion which affordsexposure for electrical connections is provided on said electricalcircuit.
 12. The optical information recording and reproduction deviceaccording to claim 11, wherein said printed coil boards are formed bysuperimposing two types of printed coils with different winding methods,such that propelling forces are generated in two orthogonal directionsdue to the magnetic force of said magnet.
 13. The optical informationrecording and reproduction device according to claim 11, wherein saidcircuit core has one or more terminals connected to external wiring,said outer foundation forms a connector portion using said terminals,and outside wiring is electrically connected to said circuit core viasaid connector portion.
 14. The optical information recording andreproduction device according to claim 11, wherein at least one amongthe laser light source which emits said light beam toward theinformation recording surface of the optical disc and the photodetectorwhich receives the returning light beam after reflection by saidinformation recording surface is mounted on and enables electricalconnection to said circuit exposure portion of said circuit core,without being covered by a package.
 15. The optical informationrecording and reproduction device according to claim 14, wherein saidlaser light source and/or said photodetector mounted on said circuitexposure portion are connected to said circuit core by wire bonding. 16.The optical information recording and reproduction device according toclaim 11, wherein a land portion which can be solder-bonded is providedon said circuit exposure portion, and capacitors, resistors, and otherelectronic components are mounted on said land portion.
 17. The opticalinformation recording and reproduction device to claim 16, wherein thesurface of said land portion is subjected to solder, gold, or otherplating treatment, enabling mounting on the land portion of saidcapacitors, resistors, and other electronic components.
 18. The opticalinformation recording and reproduction device according to claim 11,wherein a metal exposure portion exposing a portion of the circuit coreis provided on said circuit core for the purpose of solder bonding, andan adjustment plate supporting said objective lens driving device isfixed to said metal exposure portion by solder bonding.
 19. The opticalinformation recording and reproduction device according to claim 11,wherein a metal exposure portion exposing a portion of the circuit coreis provided on said circuit core for the purpose of solder bonding, anda prism holder covering a prism through which said light beam passes orother holder supporting optical components is fixed by solder bonding tosaid metal exposure portion.
 20. The optical information recording andreproduction device according to claim 11, wherein said outer foundationcomprises a liquid crystal polymer or other resin material.